I'm sure there are rich persons out there who shiver at the thought of (what they may perceive as) some low-income apartment trash wearing (thrifted) Tom Ford stuff, but then those same rich persons donate the stuff for tax purposes, thereby enabling the poor to wear such things, so...

In terms of overdressing, I couldn't care less. I, for one, don't care much for (very) casual clothes. I don't even wear polo shirts anymore (in fact, I'm considering never wearing half-sleeve anything again). I still have some jeans that see occasional use, but I'm phasing them out.

I keep thinking, what if I die today? I'd hate to be seen dead in a T-shirt/know such was the last thing I ever wore in life. :P

Yea. It can happen, but not in a way you think.
In certain circumstances, being overly elegant can give you an air of impertinence, and the results are yours to deal with for good or ill. I personally managed to use my innate impertinence to an advantage. It's like labeling yourself as "high-end goods". Of course then you need to deliver too. That said, the things you definitely DO NOT want to look like is a Russian mafia boss or a Gordon Gekko wannabe. (You'll have to trust me on this. )
If you're talking about social circles outside work, I'd build up slowly, first buttondown shirts and preppy knits, chinos instead of jeans, etc. And as you change your social communication, your social circles will either accept the new, more patrician you, or you'll find new circles.

I know a guy who overdresses for every occasion. It strikes me as odd. Part of style is dressing appropriate for every occasion. We had a meeting offsite earlier this week that was business casual. Some people took this to mean jeans and a polo shirt. I dressed nicer as I refuse to wear jeans in that environment. The guy I am referencing shows up in a full suit with a bow tie. I don't see how he doesn't feel the least bit uncomfortable so overdressed.

what you are wearing separates or even excludes you from a group. ('normal' is what everyone else is wearing and you are not.)

your clothing is indicating that you are living beyond your means. (example- magnificent wardrobe but spartan apartment or old beater car)

you are, by your clothing, upstaging a host, groom, boss or other professional superior.

people are perceiving you as a pretentious prick. (Yes, behaviour, but clothes can also have this effect on some people.)

all dressed up and no place to go.

This is all very good advice if what you wish to achieve in your dress is to fit in. But this is only one of the traditions in class menswear - it's hardly the philosophy of the dandy or the fop, for example (see the quote from Wilde, above).

I now wonder what percentage of men are dandys or fops? If it is more than 1% I would be very suprised. Over-dressing at work can detract from a bosses perception of you. Perceptions can become reality. There are plenty of bosses who will resent a peacock because the perception might be that the peacock is showing up to work to show off his clothes instead of performing his duties. This was my concern for the workplace.

your clothing is indicating that you are living beyond your means. (example- magnificent wardrobe but spartan apartment or old beater car)

I agree with everything else on your list, but this is a bit silly. One needn't spend more on all things to justify spending more on something. If it appears incongruous to others so be it. For example I refuse to buy expensive stereo equipment just because it would make my home A/V setup look "nicer" in a city where the ambient noise definitely trumps any theoretical gain in audio quality. If someone looks askance at my cheap and outdated Sony stereo, I think that says more about them than it does about me.

As someone who works in the financial services industry, there are some other rules to follow, however (this is just from my personal experience at work, so don't take what follows as a blanket statement). Things like French cuffs, contrast collars on dress shirts, and suits with pinstripes are reserved for people in a position of authority. Lowly analysts like myself should stick with more conservative dress so as not to rub certain people who can make my life very difficult the wrong way. That said, I still think I dress well without drawing attention to myself -- fitted dress shirts with spread collars, Luciano Barbera trousers, Ferragamo loafers, etc.

"Since I am obsessed with all things sartorial, I couldn’t help but be riveted by a recent Wall Street Journal story about fabulously powerful people who self-ban the wearing of suits.

Is wearing a suit now the sign of a macher manque?

In the course of my reporting travels during the past year, all of the sources with whom I interviewed who had the most power—wielding the most clout, capital and all-around largest power footprint—were all adorned in anything but a suit.

By contrast, when I recently did a favor for a friend and picked up her repaired Tag Heuer at Tourneau, the watch salesman was donning a three-piece summer-weight number that was decidedly NOT off the rack. A lucre side gig? Family money? Power user of Woodbury Common?

I’ve noticed this a lot in the service sector: they are all dressed up, while we in Corporate America are all dressed down. Even the halls of once-starchy P&G and once white-shirt-only IBM are filled with some awesomely casual gear.

The upshot is that if you want to see someone turned out in (a power suit), you are more likely to see it on the body of a Barney’s salesman than in the lobby of a midtown hedge fund. In these circles, the new uniform is the dry-cleaned, many-hundreds-of-dollars jeans paired with a bespoke shirt and couture jacket. The women are rocking the jeans with the mini blazer.

The power suit is becoming powerless. Wearing whatever you want now seems to be the new emblem of a new kind of power. As in, I am so incredibly amazing and fabulous that corporate dress codes and social norms do not apply to me.

Is this one more upside-downism in a world that seems increasingly topsy turvy?"